领先和滞后链模板中的DNA切断可以触发破裂诱导的复制
Yuanlin Xu1, Carl A Morrow1, Yassine Laksir1
1Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
Molecular cell
|November 19, 2024
概括
复制压力会导致DNA断裂,有时导致断裂诱导的复制 (BIR),这是一个变种过程. 这项研究表明,领先和落后的链断裂都可能触发BIR,特别是当分叉收延迟或Ku70缺席时.
科学领域:
- 分子生物学分子生物学
- 遗传学 遗传学是一种遗传学.
- DNA 修复机制的修复机制
背景情况:
- 复制分叉遇到未修复的DNA单链断裂 (SSB) 可能导致双链断裂 (DSB),包括单端 (seDSB) 和双端 (deDSB).
- 断裂诱导复制 (BIR) 是一种致变基因途径,与癌症发展有关,但其频率和触发因素仍然不完全理解.
- 在DSB形成和修复路径选择中,领先与落后模板链SSB的作用需要进一步研究.
研究的目的:
- 调查复制分叉和DNA单链断裂 (SSB) 之间的遭遇后,破坏诱导的复制 (BIR) 的频率和决定因素.
- 为了确定前进和落后的模板链SSB是否不同触发BIR.
- 探索复制分叉融合和非同类末端结合 (NHEJ) 蛋白对BIR的影响.
主要方法:
- 在裂变酵母中使用nicking酶,包括CRISPR-Cas9尼克酶 (Cas9n) 来产生特定于位点和链的SSB.
- 分析了这些SSB的维修结果,特别是转换为deDSB或触发BIR.
- 实验涉及操纵分叉收时间和删除非同类结合蛋白Ku70.0.的末端.
主要成果:
- 领先和落后的模板链SSB通常被转换为deDSB,通过同源重组修复.
- 这两种类型的SSB都能够触发BIR,一种突变性DNA修复途径.
- 当复制分叉收延迟或当Ku70被删除时,BIR事件的频率显著增加.
结论:
- 复制分叉所遇到的DNA单链断裂 (SSB) 可以通过同源重组修复或导致突变性断裂诱导的复制 (BIR).
- 领先和落后链SSB都可以启动BIR,在复制压力 (延迟叉融合) 或受损的非同类末端连接 (Ku70删除) 的情况下,其频率会增加.
- 这些发现为推动基因组不稳定性和癌症发展的机制提供了关键的见解.
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